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1/3xD=1/(2x4)+1/(4x6)+...+1/(98x100)
2/3xD=2/(2x4)+2/(4x6)+...+1/(98x100)
2/3xD= 1/2-1/4+1/4-1/6+...+1/98-1/100
2/3xD=1/2-1/100
2/3xD=49/100
D=147/200
a) MC :24
\(\frac{1}{3}+\frac{3}{8}-\frac{7}{12}=\frac{1\times8+3\times3-7\times2}{24}=\frac{3}{24}=\frac{1}{8}\)
b)MC : 56
\(\frac{3}{14}+\frac{5}{8}-\frac{1}{2}=\frac{3\times4+5\times7-1\times28}{56}=\frac{19}{56}\)
c) MC: 36
\(\frac{1}{4}-\frac{2}{3}-\frac{11}{18}=\frac{1\times9-2\times12-11\times2}{36}=\frac{-37}{36}\)
d) MC: 312
\(\frac{1}{4}+\frac{5}{12}-\frac{1}{13}-\frac{7}{8}=\frac{1\times78+5\times26-1\times24-7\times39}{312}=\frac{-89}{312}\)
\(\frac{7}{5}-x=\frac{36}{168}\)
\(\frac{7}{5}-x=\frac{3}{14}\)
\(x=\frac{7}{5}-\frac{3}{14}\)
\(x=\frac{98}{70}-\frac{40}{70}\)
\(x=\frac{58}{70}\)
\(x=\frac{29}{35}\)
ngủ ngủ ngủ. ngủ ngon qua ta. Kêu là đi ngủ mà còn ngồi đấy hỏi bài đc cũng tài nhỉ
2\(\frac{2}{12}\)+ X = \(\frac{5}{7}\)+ \(\frac{8}{12}\)
\(\frac{13}{6}\)+ X=\(\frac{29}{21}\)
X= \(\frac{29}{21}\)- \(\frac{13}{6}\)
X=\(\frac{-11}{14}\)
\(|2^2_{12}\)\(+x=\frac{5}{7}+\frac{8}{12}\)
\(2+x=\frac{5}{7}+\frac{1}{2}\)
\(2+x=\frac{17}{14}\)
\(x=\frac{17}{14}-2\)
\(x=\frac{-11}{14}\)
\(=\frac{1}{1\cdot2}+\frac{1}{2\cdot3}+...+\frac{1}{7\cdot8}\)
\(=\frac{1}{1}-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-...-\frac{1}{8}\)
\(=\frac{1}{1}-\frac{1}{8}=\frac{7}{8}\)
\(=\frac{1}{1.2}+\frac{1}{2.3}+...+\frac{1}{3.7}+\frac{1}{7.8}\)
\(=1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+...+\frac{1}{7}-\frac{1}{8}\)
\(=1-\frac{1}{8}+0+0+...+0\)
\(=\frac{7}{8}\)
\(\frac{12}{7}:x+\frac{2}{3}=\frac{7}{5}\)
\(\frac{12}{7}:x=\frac{7}{5}-\frac{2}{3}\)
\(\frac{12}{7}:x=\frac{11}{15}\)
\(x=\frac{12}{7}:\frac{11}{15}\)
\(x=\frac{12}{7}x\frac{15}{11}\)
\(x=\frac{180}{77}\)
\(\frac{12}{7}:x+\frac{2}{3}=\frac{7}{5}\)
\(\frac{12}{7}:x=\frac{7}{5}-\frac{2}{3}\)
\(\frac{12}{7}:x=\frac{21}{15}-\frac{10}{15}\)
\(\frac{12}{7}:x=\frac{11}{15}\)
\(x=\frac{12}{7}:\frac{11}{15}\)
\(x=\frac{12}{7}\cdot\frac{15}{11}\)
\(x=\frac{180}{77}\)
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